Logic Programming

1
Logic Programming

• Logic programming
• Various facts are asserted to be true
• On the basis of these facts, a logic program can
  infer or deduce other facts
• A query can be posed to the program
• The program applies logical deductions to answer
  the query
• Logic programming languages are sometimes called
  declarative languages

2
Logic Programming (continued)

• Logic programming has been used to write expert
  systems
• Prolog (PROgramming in LOGic)
• Developed in France at the University of
  Marseilles in 1972 by a group headed by A.
  Colmerauer

3
Logic Programming (continued)

• Prolog programs
• Consist of facts and rules
• A fact expresses a property about a single object
  or a relationship among several objects
• A rule is a declaration of an if A then B form
• We interact with the program by posing queries

4

• Figure 9.10
• A Prolog Program

5
Logic Programming (continued)

• Logic programming paradigm
• The program is a knowledge base of facts and
  rules about a certain domain of interest
• Interaction with the program posing queries to
  an inference engine (also called a query
  interpreter)

6

• Figure 9.11
• The Logic Programming Paradigm